Nietzsche actually says about free will and responsibility in the many passages, from many different books that span his entire philosophical career, that must inform any interpretation of the section on the "sovereign individual". Nietzsche identifies two preconditions for the behavioral disposition at issue, namely, promise-making: first, regularity of behavior and, second, reliable memory. Nietzsche's most important discussion of the phenomenon of "self-mastery" from Daybreak is a passage as striking evidence of Nietzsche's fatalism. Ken Gemes and Poellner suggest that Nietzsche sometimes associates the language of "freedom" with certain kinds of persons, agents whose psychic economy has a certain kind of coherence, but in so doing he has engaged in what Charles Stevenson would have called a "persuasive definition" of "freedom": he wants to radically revise the content of "freedom" while exploiting the positive valence that the word has for his readers.